availability of compressed gas

This post is about the typical butane camping stove fuel. I wondered if I'd be able to get this stuff anywhere in Mongolia at all, but it was easy to get at outdoor shops in UB. Now the question is, do I have to stock up on tons of it here and carry it, or, can I expect to be able to buy it in other aimag centers? Previously in the forum I noticed the alcohol-stove question and maybe someone will think of telling me to get a different stove.. but dammit I really like my jetboil :)